Comb regulator for electric machines



April 6, 1937. H, B'EMT 2,076,115

COMB REGULATOR FOR ELECTRIC MACHINES Filed Jun 20, 1932 Hamil? enz'Z g g WM Patented Apr. 6, 1937 UNITED STATES PATENT OFFICE COMB REGULATOR FOR ELECTRIC MACHINES Application June 20, 1932, Serial No. 618,367

Claims.-

This invention relates to electrical regulators and, among other objects, aims to provide greatly improved comb regulators of the type employed for varying resistances in electric circuits, such as the excitation circuit of a dynamo. The main idea is to provide means to insure smoothness and regularity of operation of electromagnetically actuated comb regulators throughout the range of their resistance.

Other aims and advantages of the invention will appear in the specification, when considered in connection with the accompanying drawing, wherein:

Fig. 1 is a side elevation of a regulator embodying the invention;

Fig. 2 is a top plan view of the regulator shown in Fig. 1;

Fig. 3 is a partial side elevation of a slightly modified form of regulator; and

Fig. 4 is a partial top plan view of another modified form.

Referring particularly to the drawing and to the form of regulator shown in Figs. 1 and 2, a contact path I is formed by a series of substan. tially rectangular metallic laminae or plates 2 insulated from each other and adapted to be connected to different points of the resistance to be regulated (not shown). Cooperating with the laminae or contact plates is a series of resilient and bendable metallic tines 3 forming the teeth of a comb 4. As is usual in comb regulators, the teeth, when moved out of contact with the contact plates, short-circuit a portion of the resistance connected between the laminae or plates With which they are in contact. The teeth are shown as being electrically connected at their outer ends by metallic clamping members In suitably secured to the base of the regulator and the arrangement is such that all of them normally bear against the corresponding contact plates or laminae of the contact path.

In accordance with the usual mode of operation, the regulation of the resistance is efiected by successively and consecutively bending or moving away the teeth of the comb from contact with the corresponding contact plates or laminae. This movement is shown as being produced by a pivoted lever 5 connected to turn about a pivoted pin or bolt 6 and carrying at its free end the armature l of an electromagnet or solenoid 8 which is adapted to be excited by a current corresponding with that to be regulated. The armature is normally held in the position shown by a tension spring 9 secured to its base and. the lever is positioned, in this instance, at a slight angle to the plane of the teeth of the comb.

It is well known that the pull or force of attraction exerted upon the armature by the electromagnet .or solenoid is inversely proportional to 5 the square of the distance of the armature from the core. Therefore, to secure smoothness or regularity of operation of this type of regulator it is necessary that the bending resistance of the teeth shall increase consecutively from the first 10 tooth engaged by the lever to the last tooth engaged. In other words, the resistance to bending should be proportional to the force of attraction exerted by the electronragnet or solenoid on the armature I. This is accomplished by successively increasing the cross section of the teeth from the left hand end of the comb to the right hand end, all of the teeth, in this example, being of the same length.

Referring to the modified form shown in Fig. 3, all of the teeth are shown as being of the same size or cross section but their bending resistance is increased in succession by tilting or inclining the comb at an angle to the plane of the lower ends of the contact plates or laminae. In other words, the comb 4' and the clamping members 10 are twisted or turned in a counterclockwise direction so as to bend the teeth in a warped plane. Thus, the bending resistance ofiered by the successive teeth increases from the right hand end of the comb to the left hand end in substantially the same manner as explained in connection with the comb shown in Fig. 1.

Referring to Fig. 4, the modified form of regulator there shown is designed to accomplish the same result by varying the length of the teeth. In this instance, the teeth 3" are successively shorter from the right hand end of the comb to the left hand end, the clamping members l0" being arranged at an acute angle to the lever 5". It will be seen that the shorter teeth offer successively greater bending resistance in the same manner as the teeth of the comb shown in Figs.

1 and Z. The relative inclination of the lever and the clamping members [0 therefore determine the bending resistance. In other words, the lever may be arranged at an angle to the clamping members; While the clamping members may be parallel with the axis of the contact path, this being an obvious reversal of the form shown in Fig. 4.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:

1. A switch for a resistance regulator comprising, in combination, contacts adapted to be connected to resistance elements; a series of resilient, conductive, electrically connected fingers, each one of which normally engages a corresponding contact; means movable to engage consecutively and bend the fingers in succession out of engagement with their related contacts, consecutive fingers of said series being varied in form in a manner to require that the force necessary to move each finger out of contact is greater than that necessary to move a preceding finger; and electromagnetic means having an armature, said armature being operably connected to said movable means, the increase in attraction of the electromagnetic means on its armature during the movement of the latter being opposed by the increasing resistance offered by the fingers to the bending thereof.

2. A switching device for a series or resistances comprising, in combination, electromagnetic means; an armature associated with said electromagnetic means, the pull of the electromagnetic means on the armature increasing as the armature is actuated towards the electromagnetic means; a series of contacts adapted to be connected to resistances; a series of resilient, conductive fingers, each one of which normally engages a corresponding contact, said fingers being bendable away from respective contacts to open the circuit thereto; and a lever positioned to engage said fingers and being connected to said armature to be movable thereby to bend said fingers in succession, the construction and arrangement being such that the resistance offered by each finger to separation from an engaged contact exceeds that of a preceding finger, whereby the effort required of said lever to disengage said fingers increases from one end of said series to the other as the pull of the electromagnetic means on the armature increases.

3. A switch as set forth in claim 1, wherein the fingers decrease progressively in length throughout the series thereof.

4. A switch for a resistance regulator comprising contacts adapted to be connected to resistance elements; a series of resilient, conductive, electrically connected fingers, each one of which normally engages a corresponding contact; a member to which said fingers are secured at corresponding ends, said member being inclined to the plane of said contacts whereby the fingers lie in a warped plane; and a lever positioned above said fingers and being movable to contact and bend successive fingers away from their associated contacts, the resistance to bending offered by said fingers increasing from the first finger engaged by the lever progressively throughout the entire series. I

5. An electric switch, comprising a number of flexible tines disposed in a plane, and a lever acting to successively bend said tines, the tines being of increasing cross-section from the first to the last, whereby the resistance thereof to the bending moment of the lever varies increasingly from one tine to the next.

HENRI BENIT. 

